This shows my thinking when I adjusted Animals_CIV4UnitInfos.xml
bOnlyDefensive=1 & bAnimalIgnoresBorders=1 in UnitInfo - bNeutralOnly=0 in SpawnInfo
Defensive Only - Unrestricted Spawning:
PASSIVE:
Aardvark............... AARDVARK............... iAggression = 0
African Elephant....... AFRICANELEPHANT........ iAggression = 2
African Grey Parrot.... AFRICANGREY............ iAggression = 0
African Penguin........ AFRICAN_PENGUIN........ iAggression = 0
Giant Anteater......... ANTEATER............... iAggression = 0
Armadillo.............. ARMADILLO.............. iAggression = 0
Babirusa............... BABIRUSA............... iAggression = 0
Badger................. BADGER................. iAggression = 0
Ball Python............ BALLPYTHON............. iAggression = 0
Barbary macaque........ BARBARYAPE............. iAggression = 0
Barn Owl............... BARNOWL................ iAggression = 0
Barred Owl............. BARREDOWL.............. iAggression = 0
Beaver................. BEAVER................. iAggression = 0
American Black Bear.... BLACKBEAR.............. iAggression = 1
Wild Boar.............. BOAR................... iAggression = 1
Bongo.................. BONGO.................. iAggression = 0
Booby.................. BOOBY.................. iAggression = 0
Dromedary.............. CAMEL.................. iAggression = 0
Capuchin Monkey........ CAPUCHIN............... iAggression = 0
Capybara............... CAPYBARA............... iAggression = 0
Caribou................ CARIBOU................ iAggression = 0
Cassowary.............. CASSOWARY.............. iAggression = 0
Cod.................... COD.................... iAggression = 0
Crab................... CRAB................... iAggression = 0
Crow................... CROW................... iAggression = 0
Common Spotted Cuscus.. CUSCUS................. iAggression = 0
Poison Dart Frog....... DARTFROG............... iAggression = 0
Desert Tortoise........ DESERT_TORTOISE........ iAggression = 0
Dolphin................ DOLPHIN................ iAggression = 0
Onager................. DONKEY................. iAggression = 0
Duck................... DUCK................... iAggression = 0
Dugong................. DUGONG................. iAggression = 0
Asian Elephant......... ELEPHANT............... iAggression = 1
Emu.................... EMU.................... iAggression = 0
Fennec Fox............. FENNECFOX.............. iAggression = 0
Flamingo............... FLAMINGO............... iAggression = 0
Galapagos Penguin...... GALAPAGOS_PENGUIN...... iAggression = 0
AGGRASSIVE:
Arctic Fox............. ARCTICFOX.............. iAggression = 0 (Assassinate WATERFOWL & SEABIRD)
Beluga Whale........... BELUGA................. iAggression = 0 (Assassinate CRUSTACEAN & FISH_BONEY)
Ussuri dhole........... DHOLE.................. iAggression = 0 (Assassinate ANTELOPE, BOVINE, CERVID, EQUINE & SWINE)
Dingo.................. DINGO.................. iAggression = 0 (Assassinate MARSUPIAL)
Bald Eagle............. EAGLE.................. iAggression = 0 (Assassinate BIRD_SEABIRD, BIRD_WATERFOWL & RODENT)
Ethiopian Wolf......... EWOLF.................. iAggression = 0 (Assassinate RODENT)
Can Attack - Stealth Defense - Only neutral Spawning:
PASSIVE:
Asian Black Bear....... ASIANBEAR.............. iAggression = 3 (Assassinate: SOLO & PARTY)
Bison.................. BISON.................. iAggression = 3 (Defensive Only)
Cape Buffalo........... BUFFALO................ iAggression = 3
Cave Bear.............. CAVEBEAR............... iAggression = 0
Chimpanzee............. CHIMPANZEE............. iAggression = 2
Auroch................. COW.................... iAggression = 4 (Defensive Only)
AGGRASSIVE:
Jaguar................. ANIMAL_JAGUAR.......... iAggression = 9 (Assassinate: SOLO, PARTY, CERVID, RODENT & TAPIR)
Brown Bear............. BEAR................... iAggression = 1 (Assassinate: BOVINE, CERVID, GOAT & SWINE)
Bengal Tiger........... BENGALTIGER............ iAggression = 7 (Assassinate: ANTELOPE, BOVINE, CERVID & SWINE)
Black Caiman........... CAIMAN................. iAggression = 2 (Assassinate: BIRD, CERVID, RODENT & TAPIR)
Cave Lion.............. CAVE_LION.............. iAggression = 6 (Assassinate: BOVINE, CERVID, EQUINE & URSINE)
Cheetah................ CHEETAH................ iAggression = 4 (Assassinate: ANTELOPE, RATITE, & SWINE)
Cobra.................. COBRA.................. iAggression = 2 (Assassinate: DIMINUTIVE, TINY, & SMALL)
Dire Wolf.............. DIREWOLF............... iAggression = 6
Defensive Only animals can be made able to attack by the "Savage Beast I" promotion. "Savage Beast III" will make them ignore cultural borders.